The invention relates to a method of making a rear shelf trim panel with speaker apertures to accommodate a speaker mounted under the rear shelf trim panel.
Many motor vehicles now have FM stereo radios or more elaborate sound systems such as tape players and compact disc players with accompanying speakers for the enjoyment of the driver and passengers. Many after market speakers are free standing with their own cases and speaker grills. The speaker grill is commonly used to conceal and protect the actual speaker cone against puncture or other damage. Factory mounted speakers are often mounted in concealed places such as behind door panels and under rear trim shelf panels. When the speakers are positioned behind or under such panels, the panels must incorporate a speaker grill that has apertures and cutouts to reduce muffling effects of the panels and to promote the efficiency of sound emanation from the concealed speakers into the interior of the motor vehicle.
Many known speaker grills are molded. Pins are used in the mold to form apertures through the cover to allow sound emanation. A porous cloth or non-woven fabric may provide a fabric covering for the speaker grill. While the panel needs holes to allow transmission of sound, a light porous cloth or fabric may cover the holes in the panel structure without an overly undesirable amount of sound blockage.
What is needed is an expeditious method of forming an integrated speaker grill with an automotive interior panel that has apertures incorporated therein to provide for the transmission of sound from the speaker into the automotive vehicle interior.
In accordance with one aspect of the invention, a process for forming a combined speaker grill and automotive interior trim panel includes the initial step of providing a substrate layer of a heated mat material having a content of thermoplastic material such that it is moldable under heated conditions. Preferably the mat also has a content of flax fiber. The process also includes punching a plurality of apertures in the heated substrate. The punching of the apertures is, in one embodiment, simultaneous with said molding step such that the apertures are formed through both the substrate and the decorative layer as the substrate and decorative layer are shaped into the panel.
A decorative layer is provided onto the heated substrate. The decorative layer is preferably a porous carpet with a thermal plastic back surface.
The substrate and the decorative layer are molded into the desired shaped panel such as a rear shelf trim panel such that said apertures form an integral speaker grill within the panel.
Preferably, a first and second mold dies form the apertures in the substrate. The first mold die has apertures therein and the second mold die has a punch set that fits in the apertures of the first mold die to punch apertures through both the decorative layer and the substrate as the mold dies are closed to shape the substrate and the decorative layers into the panel.
In one embodiment, the apertures in the substrate are formed before the substrate is molded into its final shape. Pins are then positioned in the apertures and the decorative layer is positioned over both the substrate and the pins in the mold. The mold is closed and the substrate layer and decorative layer are molded into a shape of an automotive interior panel under pressure.
The substrate is then removed from the pins such that its apertures are positioned under the decorative layer. The molded panel has the decorative layer spanning over the apertures in the substrate.
Preferably, the pins extend through a first mold die and are level with an interior surface of the first mold die. The apertures in the substrate are formed by a first punch set aligned with the pins to push through said substrate and recess the pins. The punch set is then raised to remove the punched scraps of substrate. The pins are then raised to intrude into the apertures in the substrate. A second mold die that complements said first mold die is provided and the panel is molded into shape with the pins extending through said first mold die and remaining in the apertures in the substrate.
In accordance with another aspect of the invention, a process for forming a combined speaker grill and automotive interior trim panel is characterized by the steps of providing a decorative layer that is capable of being bonded to said substrate layer; placing the heated substrate layer and decorative layer into an open mold; closing the mold and molding the substrate layer and the decorative layer into a formed automotive interior panel under pressure between two closed mold dies with a first mold die section having a section with a plurality of holes therein and a complementary mold die section having a plurality of punches that mate with the plurality of holes to punch a plurality of apertures in the formed panel to form an integral speaker grill with the panel; and opening the mold dies and cooling the panel to be resolidified with the substrate and decorative layers being bonded together and removing the molded formed panel and speaker grill from the mold.
In accordance with another aspect of the invention, a process for forming a combined speaker grill and automotive interior trim panel is characterized by the steps of: providing a substrate layer of a heated mat material having a content of thermoplastic material such that it is moldable under heated conditions; punching out a plurality of holes in the substrate layer; positioning a pin in each respective hole with an end of the pin substantially coplanar with one side of the substrate layer; providing a decorative layer that is capable of being bonded to the substrate layer; molding the substrate layer and the decorative layer into a formed automotive interior panel under pressure between two closed mold dies with the decorative layer spanning over the pins in the apertures in the substrate to form an integral speaker grill with the panel; removing the molded formed panel and speaker grill after the thermoplastic material in the panel is cooled to allow the panel to be resolidified and the substrate and decorative layers to be bonded together.
In accordance with another aspect of the invention, a molded interior automotive panel and speaker grill combination includes a molded substrate layer having thermal plastic content and a flax fiber content. A plurality of apertures through the substrate are aligned with a speaker mounted therebehind. A decorative layer is bonded on top of the substrate material and molded thereto. In one embodiment, the decorative layer is a porous carpet layer that spans over the plurality of apertures. In another embodiment, the decorative layer also has apertures therethrough that align with the apertures in the substrate.